We are engaged in recording the properties of ionic channels that are activated by chemical means, particularly post synaptic receptors, in tissue cultured nerve and muscle. Using fluctuation analysis to estimate single channel conductance and channel open time for a variety of channels activated by different drugs, we will also measure voltage sensitivity if possible using fluctuation techniques and voltage clamp step procedures. We will look at how different pharmacological agents, particularly central nervous system active drugs, modify post synpatic channel function. We will also attempt to record the opening and closing of single channels in order to observe channel transitions in a theory free manner. IDEN*